ENS (Ethereum Name Service) Integration

Integration with ENS (Ethereum Name Service)

ENS is the de facto standard for human-readable addresses in the Ethereum ecosystem. Instead of building your own naming service, most dApps simply integrate ENS: display names instead of addresses, accept name input in transfer fields, show avatars.

Name Resolution in Code

Frontend via ethers.js / viem

// ethers.js v6
const provider = new ethers.JsonRpcProvider(RPC_URL);

// Forward resolution: name → address
const address = await provider.resolveName("vitalik.eth");
// "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

// Reverse resolution: address → name
const name = await provider.lookupAddress("0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045");
// "vitalik.eth" or null if reverse record not set

// Avatar
const resolver = await provider.getResolver("vitalik.eth");
const avatar = await resolver?.getAvatar();
// Avatar URL or null

// viem
import { createPublicClient, http } from "viem";
import { mainnet } from "viem/chains";
import { normalize } from "viem/ens";

const client = createPublicClient({ chain: mainnet, transport: http() });

const address = await client.getEnsAddress({ name: normalize("vitalik.eth") });
const name = await client.getEnsName({ address: "0xd8dA..." });
const avatar = await client.getEnsAvatar({ name: normalize("vitalik.eth") });

normalize() is important: ENS names are normalized per UTS-46 standard before hashing. Vitalik.ETH and vitalik.eth — one name, but without normalize() they give different namehashes.

On-chain Resolution

interface IENSResolver {
    function addr(bytes32 node) external view returns (address);
}

interface IENS {
    function resolver(bytes32 node) external view returns (address);
}

contract ENSConsumer {
    IENS constant ENS_REGISTRY = IENS(0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e);
    
    function resolveENS(bytes32 namehash) external view returns (address) {
        address resolverAddr = ENS_REGISTRY.resolver(namehash);
        require(resolverAddr != address(0), "No resolver");
        return IENSResolver(resolverAddr).addr(namehash);
    }
}

Namehash for alice.eth needs to be computed off-chain (or via ENS SDK) and passed to the contract — on-chain string namehash computation is expensive.

Text Records and Profiles

ENS stores arbitrary text records by key:

const resolver = await provider.getResolver("alice.eth");

const email = await resolver?.getText("email");
const twitter = await resolver?.getText("com.twitter");
const github = await resolver?.getText("com.github");
const website = await resolver?.getText("url");
const description = await resolver?.getText("description");

Standard keys (EIP-634): email, url, avatar, description, notice, keywords, com.twitter, com.github, com.discord, org.telegram.

This is the foundation for ENS-based profiles: everything needed is stored in resolver, read without additional infrastructure.

Integration Complexity Guidelines

Basic ENS integration into existing dApp — 2-3 working days.